a. looped domain, 30-nm chromatin fiber, nucleosome, 2 nm helix b. 2 nm helix, nucleosome, 30-nm chromatin fiber, looped domain c. nucleosome, looped domain, 2 nm helix, 30-nm chromatin fiber d. looped domain, nucleosome, 2 nm helix, 30-nm chromatin fiber e. 2 nm helix, nucleosome, looped domain, 30-nm chromatin fiber
